Abstract
The paper presents a brief overview of the polymeric materials recycling problems and especially those connected with polypropylene reprocessing. It is pointed out the manner in which reprocessing of polymeric materials determines the change of the polymeric melts viscous-elastic properties and, as a consequence, the change of rheological behaviour during the recycling process. It was chosen to do the study of the extrusion reprocessing, so, it was determined, after a significantly number of recycling, the modifying of the process parameters needed in order to obtain the best performances and the highest quality of the product. There were compared the screw extruder performances in the case of the first processing and after ten times recycling of the PP. Keywords: recycling, rheological behavior, polymeric materials, polypropylene, screw extruder